is mentioned by

Thm* P:(TProp). (x:T. Dec(P(x))) (x:T. P(x) P(x))	[not_not_rw]
Thm* P:(TUProp). (x:T, y:U. Dec(P(x,y))) (p:(TU). Dec(p/l,r. P(l,r)))	[decidable__spread]
Thm* Dec(P) Dec(Q) ((P Q) (Q P))	[contrapositive]
Thm* Dec(P) Dec(Q) ((P & Q) P Q)	[demorgan2]
Thm* Dec(P) Dec(Q) ((P Q) P & Q)	[demorgan1]
Thm* Dec(P) Dec(Q) ((P Q) P & Q)	[demorgan]
Thm* (P Q) (Dec(P) Dec(Q))	[decidable_functionality_wrt_iff]
Thm* Dec(P) Dec(Q) SqStable(P Q)	[sq_stable__or]
Thm* SqStable(P) SqStable(Q) SqStable(P Q) SqStable(P) SqStable(Q)	[sq_stable_functionality_wrt_or]
Thm* P:(TZProp). (x:T, y:Z. Dec(P(x,y))) (f_p:(TZ). x:T, y:Z. P(x,y) f_p(x,y))	[decidable_iff_exists_bool_function_2]
Thm* P:(TProp). (x:T. Dec(P(x))) (f_p:(T). x:T. P(x) f_p(x))	[decidable_iff_exists_bool_function]

In prior sections: core well fnd int 1 bool 1